Cognizant — My on-boarding pass is not generating

Heloo
This is Aiswarya
Candidate ID[protected]
I received my previous DOJ at 24th april, my DOJ has been getting cancelled for the 3rd time and when i contact them they were saying it was due to technical error and most of the time my recruiter was not responding to my calls, mails and messages. This is really putting us in trouble
Am really disappointed of this behaviour from such a reputed institution .
Could you please help me to resolve this, or is there any thing that i can do from my side to resolve this.